Ultraviolet radiation is a part of solar rays with 200-400 nm of wavelength and is a part of the electromagnetic spectrum; especially UVB (Ultraviolet-B) with 280-320 nm of wavelength is the major part of the ultraviolet radiation to cause skin aging leading to skin-burn and skin cancer. When the skin is exposed to ultraviolet radiation, DNA, proteins, lipids, etc., in cells are damaged and thereby generate sunburn-cells. These sunburn-cells undergo apoptosis, accompanied by DNA fragmentation, activation of caspase, and the like. High-dose radiation on the cell causes serious DNA damages that are not recovered from; and the apoptosis prevents the cell from developing to a tumor by inducing the cell to die. Therefore, in order to prevent cancer and maintain cell homeostasis, it is very important to induce or to prevent apoptosis of the cell selectively according to the degree of cell damages.
Bcl-2 plays a very important role in the process of apoptosis of the skin cell. The Bcl-2 gene encodes 26 kDa protein present in a nuclear membrane and an outer membrane of mitochondria. Bcl-2 is a protein that inhibits apoptosis of a cell by adhering to a protein such as Bax, which accelerates the apoptosis, to inhibit its function. Therefore, apoptosis of a cell can be determined by the concentration ratio of Bcl-2 and Bax.
UVB irradiation has been known to decrease Bcl-2 expression of human keratinocyte. Furthermore, Bcl-2-transfected HaCaT cells or Bcl-2-overexpressing transgenic mice were shown to be resistant to UVB-induced apoptosis. However, over-expression of Bcl-2 prevents apoptosis of a cell with serious DNA damage and thereby causes a cancer. Therefore, it is very important to control the expression of Bcl-2 selectively.
Up to now, techniques or methods for controlling the expression of Bcl-2 have not been widely disclosed compared with the functions of Bcl-2. Only some transcription factors such as pRb, c-myb and Brn-3a in nerve cells have been disclosed. In particular, it is reported that Brn-3a, a type IV POU domain transcription factor, adheres to a P2 promoter of Bcl-2 and controls the expression of a Bcl-2 gene to protect the nerve cells from apoptosis.
However, mechanisms or factors to control the expression of Bcl-2 in HaCaT cells derived from human skin have not yet been disclosed.
In addition, a material for controlling the expression of Bcl-2 that is not toxic and is easily applied to the human body have not yet been disclosed.